1. Field of Invention
The invention relates to a thin film transistor (TFT) substrate and a display apparatus having the TFT substrate.
2. Related Art
With the progress of technologies, display apparatuses have been widely applied to various kinds of fields. Especially, liquid crystal display (LCD) apparatuses, having advantages such as compact structure, low power consumption, light weight and less radiation, gradually take the place of cathode ray tube (CRT) display apparatuses, and are widely applied to various electronic products, such as mobile phones, portable multimedia devices, notebooks, LCD TVs and LCD screens.
Generally, a display apparatus includes a display panel and a driving module. The driving module includes a scan driving circuit and a data driving circuit. The scan driving circuit is electrically coupled to the display panel through a plurality of scan lines, and the data driving circuit is electrically coupled to the display panel through a plurality of data lines. Besides, the display panel includes a plurality of pixels, and the data lines and the scan lines cross each other to form the pixel array including the pixels. When the scan driving circuit outputs a scan signal to enable the scan line, the data driving circuit transmits the data signals of each column to the corresponding pixel electrodes of the pixels through the corresponding data lines, thereby enabling the display panel to display the image.
The enabling time (i.e. scan time) of the scan signal transmitted through the scan line is determined according to the number of the scan lines and the frame rate. However, the parasitic capacitance on the pixel array of the display panel, such as the parasitic capacitance of the cross over of the data lines and the parasitic capacitance of the switch transistor (e.g. Cgd, Cgs or Csd), and the loading impedance of the pixel may deform and delay an ideal scan signal waveform. This kind of signal delay and deformation (i.e. RC distortion) will become more serious in the case of the large-scale, high definition and 3D display apparatus. For example, the sampling error of the pixel may occur so that the display panel can't correctly display. An effective means for reducing the signal delay and deformation is to decrease the impedance (R) and capacitance (C). In addition to the above-mentioned circuit design, the same effect can be also achieved by improving the efficiency of the circuit layout.
A general procedure of the circuit layout is to draw the equivalent circuit, then convert it into a layout pattern, and finally conduct the production thereby. However, an equivalent circuit can be carried out by various kinds of the layout, so the improvement of the efficiency of the circuit layout is an essential subject for the circuit design.
Therefore, it is an important subject to provide a TFT substrate and a display apparatus having the TFT substrate where the capacitance is decreased by the circuit layout and the layout efficiency per unit area is increased so as to reduce the signal delay and deformation.